The present application relates to an indium adsorbent. More specifically, the present application relates to an indium adsorbent made of a polymer material having a template architecture with respect to indium.
With a rapid development of a recent liquid crystal technology, demand for ITO (indium tin oxide) used as a transparent conductive film for liquid crystal is markedly increasing. An ITO target material is used as a material for an ITO film. In related art, some indium recovering methods have been proposed in which an ITO target scrap and the like are used as materials.
For example, Japanese Patent Application Laid-open No. HEI 08-091838 (hereinafter, referred to as Patent Document 1) discloses a method of manufacturing an indium oxide including: a first step of leaching out an indium inclusion with a nitric acid to obtain an indium nitrate solution; a second step of extracting, with an organic solvent, an indium ion from the indium nitrate solution obtained in the first step, and performing back extraction on an extract obtained, to obtain an indium aqueous solution; and a third step of hydrolyzing the indium aqueous solution obtained in the second step, and roasting an indium hydroxide obtained, to obtain an indium oxide.
Further, Japanese Patent Application Laid-open No. 2000-169991 (hereinafter, referred to as Patent Document 2) discloses an indium recovering method including: a dissolving step of dissolving an indium inclusion with a hydrochloric acid; a neutralizing step of neutralizing an obtained solution by adding alkali thereto, and causing a predetermined metal ion in the solution to precipitate to be removed; a sulfurizing step of insufflating the neutralized solution obtained with a hydrogen sulfide gas, and causing a metal ion that is harmful in a following electrolyzing step to precipitate as sulfide to be removed; and a step of performing electrowinning of an indium metal.
Furthermore, Japanese Patent Application Laid-open No. 2002-69684 (hereinafter, referred to as Patent Document 3) discloses an indium recovering method including a step of dissolving an ITO indium-containing scrap with a hydrochloric acid to obtain an indium chloride solution; a step of adding a sodium hydroxide solution into the indium chloride solution to remove tin contained in the scrap as tin hydroxide and further adding a sodium hydroxide solution to obtain indium hydroxide; a step of filtering indium hydroxide and thereafter adding a sulfuric acid to obtain indium sulfate; and performing electrowinning of indium.
On the other hand, a polymer material having a template architecture is known as a carrier for efficiently adsorbing a certain kind of adsorption-target substance. The polymer material specifically adsorbs the adsorption-target substance by preparing a polymer having a template architecture with respect to the adsorption-target substance or a part thereof.
For example, Japanese Patent Application Laid-open No. 2000-135435 (hereinafter, referred to as Patent Document 4) discloses a polymer separating agent having a template architecture with respect to an estrogen compound or an estrogen-like substance. Patent Document 4 describes that the polymer separating agent can be produced by a known method (see, paragraph 0011 in Patent Document 4). The known method herein refers to a method of mixing an estrogen compound or the like (template guest) as an adsorption target with a polymerizable monomer to be polymerized, and thereafter removing the template guest, to form a polymer having a template architecture with respect to a guest compound.